Battery - newbie

jeanacr · 11-27-2016, 03:44 PM

Hi, I'm new to dry camping and have set up what I think is a good solution for power but I'm having issues. Here's the set up.

1998 Dutchman Class C - dry camped on property with no power

I've not an experienced power person but I've looked at the usual YouTube info and done some research before I did this. Still having problems and would appreciate any suggestions.

I replaced coach battery with 2 AGM Deep Cycle batteries that are wired together. They are 120 ah each. I purchased a Bestek 400W power inverter and connected it directly to one of the batteries so that I could run some 110 things in the camper. I have a generator but don't like to run it that often. Was trying to provide some basic power through batteries.

Here's what is happening. The things plugged into the inverter don't run but a few hours before they die. This is an Internet router, wireless box and charging my phone primarily. I then have to turn on the engine to recharge things. It's almost like none of the power from the two AGM batteries is being used. I have checked them a few times with meter/charger and they show they are charged up or up to 11.x volts. Still the lights, heater, inverter, etc won't run more than a few hours. Shouldn't I be getting more from these two batteries?

My fridge runs on gas/electric and is pulling on gas as I can hear it. I don't keep any other lights on and until it started getting cold I wasn't trying to run any AC/heat at all.

Appreciate any insight as to how I have this wired or am I just asking too much?

Thanks

Rich.M · 11-27-2016, 03:57 PM

First thing that caught my attention is the "charged voltage" . A fully charged battery should be 12.6 or 12.7 volts. Your are not achieving a full charge to start or have a defective battery problem. if you are in the 11.? Voltage range then you are starting the day with only a 30% or so charge. It may be as simple as running you generator longer. If you want to boondock frequently the you may need 400watts of solar.

Rich.M · 11-27-2016, 04:11 PM

Here is a table that may help you to know the charge status based on voltage. It is not meant to be more than an estimate. The voltage is measured after the charging is finished and the batteries have time to dissipate their surface charge. ( give it 30 min to 1 hr). Your generator will charge the batteries faster than running the coach unless you are on the highway. Remember, the fridge is using power even if on gas and the heater blower fan is a power hog.

**Flybob** · 11-27-2016, 05:27 PM

Quote:

Originally Posted by jeanacr

I then have to turn on the engine to recharge things.
Thanks

If by this you mean that you are running the RV engine at idle for a while that is your problem. Running the batteries down to 50% you need at least 120AHrs to reach full charge. You say battery is reading 11.X? so you are drawing the battery below 50%. To add 120AHrs to the battery, you will need several hours on the road at highway speeds. You can not accomplish this running at idle.

jeanacr · 11-27-2016, 06:40 PM

Thanks for your replies. Sounds like I really need to run the generator to fully charge the batteries. It's semi-permanently parked so I can't run it down the road. I'll experiment with generator charging as more than one person has said that's the best thing to do.

The other thing I'm concerned about is how I have the batteries wired. I have both + and - from the camper connected to the first battery. Someone said that I should have the negative connected to the last battery (they are run parallel). Is that true? Maybe that's part of the reason it's not giving me juice for as long as it should.

Thoughts?

rockfordroo · 11-27-2016, 06:46 PM

Quote:

Originally Posted by jeanacr

Thanks for your replies. Sounds like I really need to run the generator to fully charge the batteries. It's semi-permanently parked so I can't run it down the road. I'll experiment with generator charging as more than one person has said that's the best thing to do.

The other thing I'm concerned about is how I have the batteries wired. I have both + and - from the camper connected to the first battery. Someone said that I should have the negative connected to the last battery (they are run parallel). Is that true? Maybe that's part of the reason it's not giving me juice for as long as it should.

Thoughts?

Read this.

spock123 · 11-27-2016, 07:01 PM

You need to google the 12 volt side of life part one. It will tell you what you need to know about batteries.

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rockfordroo · 11-27-2016, 07:22 PM

Quote:

Originally Posted by spock123

You need to google the 12 volt side of life part one. It will tell you what you need to know about batteries.

Sent from my iPhone using Forest River Forums

Here it is.

Unfortunately, it doesn't show the proper way to wire multiple batteries; which is why I gave him only what he asked for.

I'm also giving him a somewhat better overall view of the typical RV electrical system than The 12 Volt Side of Life does. (And even this one doesn't address coach vs chassis batteries for MH's).

**Flybob** · 11-27-2016, 08:09 PM

Your problem has nothing to do with the way you have batteries connected together. The value of the two different connection methods has been debated on the forum several times. They are very close but are not causing your problem. Your issue is that you are not charging the batteries sufficiently with your engine idle method.

jeanacr · 11-27-2016, 08:23 PM

Great info!! Thank you!

glarior · 11-28-2016, 01:32 AM

Check the amp hour on your AGM batteries. I have learned the hard way that it may state a number in amp hours but in fine print it will say @ 1amp.

If their is fine print on your batteries that is why they are not lasting long. The standard rating for amp hours is @ 20 hours. If you look at the batteries manufacturer website they usually state the amp hours at a certain rate.

spock123 · 11-28-2016, 07:27 AM

Quote:

Originally Posted by rockfordroo

Here it is.

Unfortunately, it doesn't show the proper way to wire multiple batteries; which is why I gave him only what he asked for.

I'm also giving him a somewhat better overall view of the typical RV electrical system than The 12 Volt Side of Life does. (And even this one doesn't address coach vs chassis batteries for MH's).

I personally like the 12 volt side of life, it's easy to understand. It's a good place to start if you know nothing about batteries.

Sent from my iPhone using Forest River Forums

jeanacr · 12-01-2016, 06:40 PM

Thought I would update folks- batteries were checked at store and determined to be dead. They replaced them and we are charging mor often with generator as we closely monitor them.

After reconnecting we have a new problem- RV heater won't work unless we run generator. We're double checking connections but if we don't find anything there any ideas?

Thanks

PhoneDude 8289 · 12-01-2016, 08:14 PM

Get a good battery charger like the 4 stage 5 amp battery tender smart charger. There are several good brands out there I happen to like the battery tender. It will do you a good job and your batteries will love it. The converters that come with most of these rigs are not the best in the world for charging batteries.

NMWildcat · 12-01-2016, 08:23 PM

Quote:

Originally Posted by jeanacr

Thought I would update folks- batteries were checked at store and determined to be dead. They replaced them and we are charging mor often with generator as we closely monitor them.

After reconnecting we have a new problem- RV heater won't work unless we run generator. We're double checking connections but if we don't find anything there any ideas?

Thanks

12v fuses?

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